Harris W F
Department of Optometry, Rand Afrikaans University, Johannesburg, South Africa.
Optom Vis Sci. 1992 Nov;69(11):835-45. doi: 10.1097/00006324-199211000-00002.
Transformation of dioptric power from the conventional clinical representation as sphere, cylinder, and axis to the vectorial representation known as the vector h makes it possible to apply formal multivariate statistical methods to dioptric power. Methods are described for testing hypotheses on mean dioptric power and on variance-covariance of dioptric power for one and more than one population. A number of numerical examples are presented. Attention is drawn to the underlying assumption of multivariate normality, to other limitations of the methods, and to pitfalls in the use of the methods. Three-dimensional scatter plots, shown by means of stereo-pair drawings, are useful for detecting departures from normality.
将屈光力从传统临床表示形式（球镜、柱镜和轴位）转换为称为矢量h的矢量表示形式，使得将形式化多变量统计方法应用于屈光力成为可能。本文描述了针对一个及多个总体的平均屈光力以及屈光力的方差协方差进行假设检验的方法。给出了一些数值示例。文中提请注意多变量正态性的潜在假设、这些方法的其他局限性以及使用这些方法时的陷阱。通过立体对图展示的三维散点图有助于检测偏离正态性的情况。
